Extraction connection for double casing machine



Sept. 20, 1966 J. J. JACOBS ETAL 3,273,510

EXTRACTION CONNECTION FOR DOUBLE CASING MACHINE Filed July 16, 1964 Jpmz/ Z J. Jam/ 0 "ED vial @i. @5010) United States Patent 3,273,510 EXTRACTION CONNECTION FOR DOUBLE CASING MACHINE Joseph J. Jacobs, Trenton, N.J., and David R. Basco,

Wauwatosa, Wis., assignors to Allis-Chalmers Manufacturing Company, Milwaukee, Wis.

Filed July 16, 1964, Ser. No. 383,024 3 Claims. (Cl. 103-111) This invention pertains in general to a double casing machine and more particularly to an extraction connection for such a machine.

Although it is not intended to be so limited, this invention has particular application to multistage centrifugal pumps such as boiler feed pumps. Because of the high pressures and temperatures involved, it is comm-on practice to provide both an inner and outer casing for such pumps. Since the inner casing is exposed to higher temperatures and pressures than the outer casing, provision is made to permit relative radial and axial movement between the two casings. Because of this relative movement, it is difilcult to provide a fluid tight connection through the outer casing into the inner casing to extract pressurized fluid therefrom. Provision to accommodate this relative movement must be provided in the extraction connection.

It is applicants intention and the general object of this invention to provide a fluid tight extraction connection for a double casing machine which permits relative axial and radial movement between the inner and outer casings of the machine.

A further object of the subject invention is to provide an extraction connection for a double casing machine wherein a flexible conduit is rigidly connected to the inner casing and sealed to the outer casing in a manner to permit relative axial and radial movement therebetween.

A more specific object of the subject invention is to provide an extraction connection for a double casing machine wherein a self-energizing O-ring seal can be utilized.

An additional object of the subject invention is to provide an extraction connection for a double casing machine wherein a flexible conduit is threadably received into the inner casing and has a shoulder thereon which is of a diameter substantially equal to the diameter of the opening through the outer casing wherein the conduit is of suificient length so as to assure threaded engagement with the inner casing prior to entrance of the oversize shoulder into the opening through the outer casing.

These and other objects of the subject invention will become more fully apparent as the following description is read in light of the attached drawing, wherein:

FIG. 1 is a cross sectional view showing the takeoif conduit initially engaged with the inner casing;

FIG. 2 is a cross sectional view showing the takeoff conduit in place; and

FIG. 3 is an enlargement of a portion of the O-ring and adjacent structure shown in FIG. 2.

Referring to the drawing, the invention is shown in connection with a machine having an outer casing 4 and an inner casing 6. The inner casing has a chamber 7 therein which contains the high pressure high temperature fluid being acted upon by the machine. A passageway 8 connects the chamber 7 with an internally threaded opening 9 through the outer wall of the inner casing.

The outer casing 4 is provided with an opening 11 therethrough which is in substantial alignment with the threaded opening in the inner casing 6. An elongated pipe 12 may be rigidly connected to the outer casing in any conventional manner such as by welding 13. The pipe 12 may be provided with a conventional mounting flange 14 to receive a valve (not shown) to control the extraction of the fluid.

A flexible conduit 16 is received within the walls of the pipe 12 and the opening 11. The lower end of the conduit 16 is provided with an external thread 17 which mates with the internally threaded opening 9. On the opposite end of the conduit 16 is a shoulder 18. This shoulder is of a diameter substantially equal to the internal diameter of the pipe 12, whereas the external diameter of the conduit 16 is considerably less than the internal diameter of the pipe 12 and the opening 11. To facilitate assembly of the conduit 16 into the threads 9 of the inner casing 6, the distance between the inner surface 19 of the shoulder 18 to the end of the threads 17 is greater than the distance between the end 21 of the pipe 12 and the outer surface 22 of the casing 6. Because of this greater distance, the threads 17 engage the threads in the opening 9 prior to entry of the shoulder 18 into the interior of the pipe 12. Since the diameter of the conduit 16 is considerably less than the internal diameter of the pipe 12 and the opening 11, any misalignment between the inner and outer casings will not interfere with installation of the conduit 16. If the threads in the opening 9 are out of alignment with the opening 11, the conduit 16 can be moved to either side of the opening 11 so that the threads will engage. Once the mating threads are engaged, the flexible conduit 16 can be bent to force the shoulder 18 into the interior of the pipe 12. With this type of connection, an inexpensive arrangement is provided which is not hindered by misalignment between the inner and outer casings of the machine.

Once the conduit 16 has been started into the threads in the opening 9, it is turned down until the shoulder 23 at the end of the threads 17 engages a gasket 24 on the outer surface of the inner casing 6. In this position the shoulder 18 is in the position shown in FIG. 2 within the interior of the pipe 12. A self-energizing O-ring 25 is then placed above the conduit 16 above the shoulder 18. A pressure ring 26 having internal threads thereon may then be turned onto external threads 27 provided at the outer end of the conduit 16 belond the shoulder 18.

This provides an adequate seal between the atmosphere and the space between the conduit 16 and the pipe 12. Furthermore, as the pressure in this area increases, a more eifective seal is created due to the self-energizing feature of the O-rign 25. The self-energizing feature is a series of openings 28 (FIG. .3) through the wall of the O-ring' so oriented as to be exposed to the high pressure fluid in the area between the conduit 16 and pipe 12. This permits entrance of the pressurized fluid into the interior of the O-ring to force or expand the O-ring outward into a more forceful engagement with the sealing surfaces of the conduit 16 and the pipe 12.

Although only one embodiment of the subject invention has been herein shown and described, other modifications will be apparent to those skilled in the art after reading this description, and it is intended that all such modifications as come within a reasonable interpretation of the appended claims he covered.

Having now particularly described and ascertained the nature of our said invention and the manner in which it is to be performed, we declare that what we claim is:

1. An extraction connection for a machine having in ner and outer casings comprising: walls defining a first threaded opening through the outer 'wall of said inner casing; walls defining a second opening through the outer wall of said outer casing in substantial alignment with said threaded opening; an externally threaded conduit threadably engaged within said threaded opening and passing through said second opening, the outside diameter of said conduit being less than the diameter of said second opening to permit lateral deflection of said conduit within said second opening; an annular shoulder on said conduit having an outside diameter substantially equal to the diameter of said second opening, said shoulder being positioned in said second opening when said threaded engagement is completed, the distance between said shoulder and the threaded end of said conduit being greater than the distance between the outer surface of said inner casing and the outer end of said walls defining said second opening to permit said threaded engagement to be initiated prior to insertion of said shoulder into said second opening; and means associated with said shoulder and said walls of said second opening providing a fluid tight seal therebetween.

2. An extraction connection for a machine having inner and outer pressurized casings comprising: walls defining a first threaded opening through the outer wall of said inner casing; walls defining a second opening through the outer wall of said outer casing in substantial alignment with said threaded opening; a flexible conduit having external threads on one end thereof thread-ably received within said threaded opening and passing through said second opening, the outside diameter of said conduit being less than the diameter of said second opening to permit lateral deflection of said conduit, said conduit and said walls of said second opening defining an annular chamber in communication with the interior of said outer casing; an annular shoulder adjacent the other end of said conduit having an outside diameter substantially equal to the diameter of said second opening; a selfenergizing O-ring positioned around said conduit and spaced from the outer surface of said shoulder, said O- ring having openings therein facing said annular shoulder and exposed to the pressure in said annular chamber; and means connected to said conduit on the outer side of said O-ring to resist axial movement of said O-ring on said conduit as the pressure in said annular chamber increases.

3. An extraction connection for a machine having inner and outer pressurized casings comprising: walls defining a first threaded opening through the outer wall of said inner casing; walls defining a second opening through the outer wall of said outer casing in substantial alignment with said threaded opening; a flexible conduit having external threads on one end thereof threadably received within said threaded opening and passing through said second opening, the outside diameter of said conduit being less than the diameter of said second opening to permit lateral deflection of said conduit, said conduit and walls of said second opening defining an annular chamber in communication with the interior of said outer casing; an annular shoulder adjacent the other end of said conduit having an outside diameter substantially equal to the diameter of said second opening, the distance between said shoulder and the threaded end of said conduit being greater than the distance between the outer surface of said inner casing and the outer end of said walls defining said second opening; a self-energizing O-ring positioned around said conduit and spaced from the outer surface of said shoulder, said O-ring having openings therein facing said annular shoulder and exposed to the pressure in said annular chamber; and means connected to said conduit on the outer side of said O-ring to resist axial movement of said O-ring on said conduit as the pressure in said annular chamber increases.

References Cited by the Examiner UNITED STATES PATENTS 1,849,217 3/1932 Aisenstein 103-108 2,367,134 1/ 1945 Mierley 25539 2,554,622 5/1951 Jones 25339 2,837,360 6/1958 Ladd.

MARK NEWMAN, Primary Examiner.

HENRY F. RADUAZO, Examiner. 

1. AN EXTRACTION CONNECTION FOR A MACHINE HAVING INNER AND OUTER CASINGS COMPRISING: A WALLS DEFINING A FIRST THREADED OPENING THROUGH THE OUTER WALL OF SAID INNER CASING; WALLS DEFINING A SECOND OPENING THROUGH THE OUTER WALL OF SAID OUTER CASING IN SUBSTANTIAL ALIGNMENT WITH SAID THREADED OPENING; AN EXTERNALLY THREADED CONDUIT THREADABLY ENGAGED WITHIN SAID THREADED CONDUIT THREADABLY ENGAGED WITHIN SAID THREADED OPENING AND PASSING THROUGH SAID SECOND OPENING, THE OUTSIDE DIAMETER OF OPENING TO PERMIT LATERAL DEFLECTION OF SAID CONDUIT WITHIN SAID SECOND OPENINGS; AN ANNULAR SHOULDER ON SAID CONDUIT HAVING AN OUTSIDE DIAMETER SUBSTANTIALLY EQUAL TO THE DIAMETER OF SAID SECOND OPENING, SAID SHOULDER BEING POSITIONED IN SAID SECOND OPENING WHEN SAID THREADED ENGAGEMENT IS COMPLETED, THE DISTANCE BETWEEN SAID SHOULDER AND THE THREADED END OF THE SAID CONDUIT BEING GREATER THAN THE DISTANCE BETWEEN THE OUTER SURFACE OF SAID INNER CASING AND THE OUTER END OF SAID WALLS DEFINING SAID SECOND OPENING TO PERMIT SAID THREADED ENGAGEMENT TO BE INITIATED 